# On the Stability of $\Lambda(1405)$ Matter

## TL;DR

This study investigates the hypothetical stability of strange matter composed of $ ext{Λ}^*(1405)$ baryons using many-body relativistic mean-field calculations, finding it unstable at large scales and incompatible with experimental kaonic atom data.

## Contribution

The paper provides the first detailed many-body analysis of $ ext{Λ}^*(1405)$ matter stability, challenging previous hypotheses of its absolute stability.

## Key findings

- $ ext{Λ}^*$ matter saturates at large A, indicating instability.
- The $ ext{Λ}^* ext{Λ}^*$ interaction model does not match kaonic atom data.
- $ ext{Λ}^*$ aggregates are unstable against strong decay.

## Abstract

A hypothesis of absolutely stable strange hadronic matter composed of $\Lambda(1405)$ baryons, here denoted $\Lambda^*$, is tested within many-body calculations performed using the Relativistic Mean-Field approach. In our calculations, we employed the $\Lambda^*\Lambda^*$ interaction compatible with the $\Lambda^*\Lambda^*$ binding energy $B_{\Lambda^*\Lambda^*}=40$~MeV given by the phenomenological energy-independent $\bar{K}N$ interaction model by Yamazaki and Akaishi (YA). We found that the binding energy per $\Lambda^*$, as well as the central density in $\Lambda^*$ many-body systems saturates for mass number $A\geq120$, leaving $\Lambda^*$ aggregates highly unstable against strong interaction decay. Moreover, we confronted the YA interaction model with kaonic atom data and found that it fails to reproduce the $K^-$ single-nucleon absorption fractions at rest from bubble chamber experiments.